A man who has been behind bars for a decade for killing a woman is suspected in the slayings of seven people whose bodies were found buried in the woods behind a Connecticut shopping center, a government official said Tuesday.

William Devin Howell, 45, has been identified as the suspect in the serial killings that have sent a chill through this working-class Hartford suburb of 73,000, the official said.

The official was briefed on the investigation but was not authorized to discuss the case and spoke to The Associated Press on condition of anonymity.

On Monday, police announced the discovery of four more bodies last month in the woods where three partial skeletons were found in 2007. All seven victims were believed to have been killed a decade or more ago by the same person, investigators said. But police added - without explanation at the time - that the killer was no longer a threat to the public.

Howell is serving a 15-year sentence for manslaughter in the 2003 killing of Nilsa Arizmendi, a 33-year-old woman who was last seen in his van in Connecticut, where he had been cutting grass and doing other odd jobs.

He was arrested in 2005 in Virginia, and a search of his van turned up blood from Arizmendi and another, unidentified person, police said. Arizmendi's body has not been found.

Investigators have not disclosed how the seven victims were killed or how authorities concluded the deaths were the work of one person.

Howell has not been charged in the crimes, and the AP could not immediately determine whether he has an attorney.

"It's definitely eerie. You stare at the woods and dead bodies are back there," said Colin Meyer, manager of a nearby muffler and brake shop. "It just makes you wonder though how many more could be back there. All there is is questions and no answers yet."

On the other side of the 15-acre patch where the bodies were found, Joe Greca, a 64-year-old business owner, said he has begun closing the drapes on his windows at night.

"It worries me because I face the woods, and I never know who's going to be coming near my backyard," Greca said.

The four victims who have been identified so far disappeared in 2003, and police said the others appeared to have been left behind a decade ago or more.

A hunter came upon the remains of the first three victims - Diane Cusack, Joyvaline Martinez and Mary Jane Menard. Police said all three women had drug or alcohol problems and were known to frequent the same downtown New Britain neighborhood.

Investigators returned annually to the site, and this spring a cadaver-sniffing dog on loan from the FBI helped locate the additional victims. One was identified as Melanie Ruth Camilini, a mother of two from Seymour.